Terminal device



J. H. STALEY TERMINAL DEVICE July 6, 1937.

Filed Dec. 2, 1835 Allow/7am.

Patented July 6, 1937 UNITED STATES.

PATENT OFFICE TERMINAL DEVICE Joseph H. Staley, Columbus, Ind.

Application December 2, 1935, Serial No. 52,538'

3 Claims (01. 173-324) This invention relates to mercury tube switches switches without having to change mountings and the like.

A further important advantage of the invention is that the metallic wall switch may be employed in damp places or places where'much dust may accumulate so that by reason of the use of the invention, the two parts of the metallic wall comprising the electrodes of the switch may not be bridged over by moisture and dust. A further important object of the invention is to provide a very simple, efiicient and low cost means for suitably insulating the metal wall switch all in a manner that will not detract from the operating eiiiciency of the switch even under severe conditions.

These and other advantages and objects of the invention will become apparent to those versed in the art in the following description of one particular form of the invention as illustrated in the accompanying drawing, in which Fig. 1 is a side elevation of a structure embodying my invention;

Fig. 2, a longitudinal central section on the line 2-2 in Fig. 1;

Fig. 3, a view in perspective of one terminal piece;

Fig. 4, a view in perspective of a second terminal piece, and

Fig. 5, a transverse section on the line 55 in Fig. 2.

Like characters of reference indicate like parts throughout the several views in the drawing.

The particular mercury tube switch shown herein as one particular form to which my invention may be applied is that as illustrated in my Patent No. 1,906,118, issued April 25, 1933, wherein a body I0 forms one terminal or electrode by an exterior cylindrical surface and, a cap N forms the other electrode by a similar cylindrical surface, the cap being insulated from the body l0 by an intervening insulating member I2.

I provide a terminal piece generally indicated by the numeral l3, Fig. 3, having its major portion longitudinally corrugated or bent to provide the outer longitudinal edges I4 and I5 with an intervening central ridge l6. From one end of the member I3 is turned a tongue I! herein shown as having a hole l8 through the tongue.

This member I3 is placed on the cap II to have the ridge I6 longitudinally contacting the cap with the edges M and I5 also contacting the longitudinal surface of the cap in spaced relation on the respective sides of the rib l6, whereby in fact, the terminal member l3 makes contact with the cap I I along three lines.

A tubular piece IQ of insulating material having an internal diameter closely approximating the external diameter of the cap and body of the switch is then entered over the end of the cap II and around the outside of the member l3 and pressed longitudinally therealong so as to tend to compress the member l3 snugly against the cap causing a concentrated pres- 7 sure to be applied on the member I3 to bring itinto forced line contacts with the cap. The tongue I! is turned downwardly across the outer end of the cap II to serve initially as a limiting stop to prevent longitudinal travel of the member l3 along the cap II as the tube I9 is pressed thereover.

The body In is provided with a transverse slot 1 20 such as would be formed by sawing a kerf across the body. A second terminal member generally designated by the numeral 2|, Fig. 4, has its major portion formed similarly to that of the piece L3 to have the central longitudinal ridge 22 with the outlying regularly up-turned edges 23 and 24. One end of this member 2| is provided with a short tongue 25 turned from the principal portion thereof while the other end is provided with a longer tongue 26 herein shown as having a hole 21 therethrough.

This member 2|, is placed on the body In to have the tongue 25 entering the slot 20 and the tongue 21 hanging over the outer end of the body. As the tube l9 is forced along from the cap H and over onto the body I0, it will pass over the member 2| tending to compress it snugly. against the side of the body H3 and bring it into the three line contact therewith as determined by the center line 22 and the outer lines of the edges 23 and 24. The tube is pressed on over the member 2| until it extends at least to the outer endof the body l0 and preferably-a slight distance therebeyond. By reason of the tongue 25 engaging in the slot 20, the member 29 is not shifted along the body l0 but is held firmly in position thereon as the tube l9 slides over the member 2|.

The terminal members l3 and 2| are made out of any suitable electrically conducting metal. The tube I9 is made out of any suitable insulating material having a slight resiliency or at least 55 suificient resiliency to prevent the tube from tearing or breaking as it is pressed over the members l3 and 21 and also as will cause it to permanently retain the members l3 and 2| in compressive contact with the cap and body of the switch. One suitable material for the tube I9 is a vulcanized or thermo-plastic material formed in conjunction with paper or fiber.

A pigtail 28 has one end of its conductor 29 attached to the terminal member l3 as indicated in Fig. 2 and is preferably soldered thereto. Likewise the pigtail 30 is connected to the other terminal member 2| to form an electrical connection therewith such as by soldering the conductor 3| to the tongue 26, the holes in the respective tongues I! and 26 aid in permitting engagement of the conductors therewith and in the soldering operation. The tube I9, while not necessarily so, is preferably cut to a length to extend slightly beyond the outer end of the cap H as indicated in Fig. 2 so as to provide an outer wall to confine an insulating medium which is employed to cover over the end of the cap. An insulating composition which is plastic initially is applied to the end of the cap H and carried outwardly along the pigtail 28a sufiicient distance such that when'the material sets, the pigtail so surrounded by that material will be held rigidly and not permitted to bend therewithin, thus protecting the connection of the pigtail with the member 13. This insulating composition indicated by the numeral 32 is commercially called cable lacquer and is well known for the purpose and is of that nature which will set and harden but not become so rigid as to lose its resiliency. Similarly the material 32 is filled in accordance with the end of the body IQ and built out a slight distance around the pigtail 30 all as indicated in Fig. 2.

The tube I9 preferably has a comparatively thin wall and is also preferably made in a black color with a dull finish so as to permit rapid heat radiation whereby heat arising within the switch due to arcing may be readily dissipated and not allowed to build up within the switch.

While I have herein shown and described my invention in one particular form, it is obvious that structural variations may be employed without departing from the spirit of the invention and I, therefore, do not desire to be limited to that precise form beyond the limitations as may be imposed by the following claims.

I claim:

1. A terminal member having a major elongated portion with a longitudinal corrugation and both edges parallel with the corrugation bent in the same direction as the corrugation and a tongue formed by bending an uncorrugated end of the member transversely of the corrugated portion.

2. In combination with a cylindrical metallic envelope, a cylindrical insulating sleeve telescoping theenvelope, and a terminal member superficially carried between the sleeve and the envelope, said terminal member having a major portion comprising two corrugations on one side and'a single corrugation on the other between the two forming a three-line contact with therespective envelope part under pressure exerted by the surrounding sleeve.

3. In combination with a metallic envelope, an insulating sleeve, and a terminal member carried between the sleeve and the envelope, said terminal member having a portion corrugated in effect whereby said sleeve may press said portion around a curving wall of the envelope into three'lines of contacts therewith.

JOSEPH H. STALEY. 

